Method and apparatus for detecting a break in longitudinally moving yarn

ABSTRACT

The disclosure of this specification relates to detecting yarns comprising displacing longitudinally moving yarn in a lateral direction to intermittently and repeatedly interrupt a light beam acting on a light sensitive device responsive to the intensity of light thereon, detecting the period for which the light beam is interrupted during lateral displacement of the yarn, emitting a signal in response to the detected period and utilizing the signal, or variations from a predetermined signal, to activate a yarn-handling device.

United States Patent [72] Inventor Geoffrey Alan Dent Fence, near Bumley, England [21] App]. No. 881,224 [22] Filed Dec. 1, 1969 [45] Patented Nov. 16, 1971 [73] Assignee Crabtree Engineering Group (Colne) Limited Lancashire, England [32] Priority Dec. 18, 1968 [33] Great Britain [31] 60,081/68 [54] METHOD AND APPARATUS FOR DETECTING A BREAK llN LONGITUDINALLY MOVING YARN Primary Examiner Ronald L. Wibert Assistant Examiner-Orvill B. Chew, ll Attorney-Stevens, Davis, Miller & Mosher ABSTRACT: The disclosure of this specification relates to detecting yarns comprising displacing longitudinally moving yarn in a lateral direction to intermittently and repeatedly interrupt a light beam acting on a light sensitive device responsive to the intensity of light thereon, detecting the period for which the light beam is interrupted during lateral displacement of the yarn, emitting a signal in response to the detected period and utilizing the signal, or variations from a predetermined signal, to activate a yarn-handling device.

PATENTEnunv 1s zen SHEET 1 0F 2 PATENTEDRUV 15 I8?! 3,621,267

SHEET 2 OF 2 METHOD AND APPARATUS FOR DETECTING A BREAK llN LONGITUDINALLY MOVING YARN This invention relates to a method and apparatus for detecting yarn during longitudinal movement of the yarn, for example, through spinning or draw twist frames as well as winding machines.

By the term yarn as referred to throughout this specification we include, filaments, threads, thin wires, strands and the like of natural or synthetic material (both textile and otherwise).

The present invention is particularly applicable to the detection of textile yarns during their longitudinal movement through textile machinery and, for convenience, the invention will be considered in its relation to such machinery.

If a yarn breaks during its passage through a textile machine the loss in production, damage to machinery and damage to neighboring yarns can be costly and cause a lot of inconvenience.

It has hitherto been proposed to provide a sensing device which mechanically contacts and detects the passage of yarn as it moves longitudinally through a machine so that when the yarn breaks the mechanical contact of the sensing device is automatically triggered and appropriate action taken as a result.

It is an object of the present invention to provide a method of, and apparatus for, detecting yarns without mechanical contact thereto and by which a signal is emitted which corresponds to a break occurring in the yarn during its movement through a machine.

According to the present invention there is provided a method of detecting a yarn during its longitudinal movement through yarn-handling apparatus which comprises displacing the yarn in a lateral direction during its run through the apparatus to intermittently and repeatedly interrupt a beam of light acting on a light-sensitive device responsive thereto so that the intensity of light on the device is repeatedly and intermittently decreased and increased, detecting the time period for which the light beam is interrupted during each lateral movement of the yarn therethrough and emitting a signal in response to said detected period to a desired yarn handling, recording or indicating device which device is actuated in response to the emitted signal or to the emitted signal when said signal differs from a predetermined signal or range of signals or to the discontinuance of an emitted signal.

Further according to the present invention there is provided apparatus for detecting or quantifying a yarn during its movement through yarn-handling apparatus which includes means for longitudinally moving the yarn; a light source and a lightsensitive device, the light source providing a beam which is adapted to be directed onto the light-sensitive device, said device being responsive to the intensity of said beam and being adapted to emit a signal in response to variations in said intensity; and displacement means adapted to impart lateral movement to the yarn during its longitudinalrun through the apparatus whereby, during its lateral movement, the yarn intermittently and repeatedly interrupts the light beam applied to the light-sensitive device and signals are emitted by said device in response to variations in intensity of said beam during the lateral movement of yarn therethrough, the emitted signals, or variations in said emitted signals from a predetermined signal or range of signals, or the discontinuance of which emitted signals, being adapted to actuate a required yam-handling device, indicating or control mechanism associated with the yarn-handling apparatus.

On draw twist frames and spinning machines the yarn moves longitudinally through the machine and is wound onto a rotating spindle to form a package. The yam position above the package is controlled by an eyelet which forms part of a lappet holder. While being wound, the yarn is laterally displaced as a result of the centrifugal force to which it is subjected and describes a laterally disposed circle about the axis of the spindle to provide an effect which is commonly known in the textile art as ballooning." A similar ballooning effect is achieved when the yarn is drawn axially from a spindle. Preferably the lateral displacement of the yarn as required by the present invention is achieved as a result of the ballooning effect so that during arcuate movement of the length of yarn which exhibits ballooning the light beam is interrupted twice during each revolution which describes the balloon."

The present invention will hereinafter be considered in its use with yarn which exhibits ballooning" but it is to be appreciated that lateral displacement of the yarn can be achieved independently of the ballooning effect, for example, by the reciprocatory action of a winding machine which intermittently and repeatedly displaces the longitudinally moving yarn laterally through the light beam.

The light-sensitive device (detector) is arranged so that for each cycle of the ballooning part of the yarn, the yarn passes very close to the light-sensitive device and in so doing reduces the light intensity for a given period. This period depends both on the angular velocity exhibited by the yarn and also on the size (i.e., thickness or diameter) of the yarn, There is also a decrease in the intensity of light applied to the light-sensitive device as the yarn passes adjacent the light source but, depending to a large extent on the effective diameter of the balloon" at the beam and the width of the beam, such a decrease in intensity may be insignificant, The signals emitted by the light sensitive device can be processed in several ways to result in the performance of a required operation or registration. The present invention can be used solely'to provide a yarn movement detector by which the yarn is so monitored that, if a break occurs, the discontinuance of an emitted signal causes, for example, an alarm to be operated, the yarn-handling machine to stop, or a cutter device to operate which severs the yarn in the machine from its source (usually frec-running creels) thereby preventing further yarn being drawn into the machine.

Conveniently the light source and light-sensitive device of the present invention are carried on a lappet holder and preferably these are mounted in housings provided in a plastics lappet holder.

Several embodiments of the present invention will now be described, by way of example only, with reference to the accompanying illustrative drawings in which:

FIG. 1 illustrates a simplified form of draw twist frame in which filament yarns are normally processed and which includes means for detecting the yarn in accordance with the invention, said means detecting a ballooning yarn;

FIG. 2 partly illustrates a lappet holder which carries the light source and light-sensitive device incorporated in the yarn-detecting means of FIG. 1;

FIGS. 3 and 4 are sectional views of the lappet holder shown in FIG. 2 taken on the lines Ill-III and l'V-IV respectively;

FIG. 5 diagrammatically illustrates a system for detecting yarn which system is responsive to variations in light intensity on the light-sensitive device in the detecting means shown in FIGS. l to 4, and

FIG. 6 diagrammatically illustrates a system similar to that shown in FIG. 5 but which is modified to indicate the length of yarn run through the draw twist frame.

In the draw twist frame shown in FIG. I, the yarn 2 is drawn from a free-running supply creel 1 and through the eyelet ofa lappet holder 3 by draw rollers 4 where it is wound on to a final package 6 which is formed on a rotating spindle 5. The longitudinally moving yarn 2 is caused to rotate about the final package 6 and in so doing a ballooning effect is set up at 2a. The yarn is guided by a lappet holder 7 which has a form of yarn guide positioned in the yarn tract. A detector/light source combination (shown generally at 7') is positioned below the yarn guide, but not in contact with the yarn as will hereinafter be described with reference to FIGS. 2, 3 and 45. The light source and detector (or light-sensitive device) are positioned so that they have a common light axis which is interrupted by the ballooning yarn 2a. This means that the light beam is interrupted twice for every rotational cycle of the yarn. Consequently, the intensity of light falling on the detector of 7' va ries in accordance with the ballooning, and signals from the detector are emitted in response to this variation in light intensity. These signals are affected by (a) balloon frequency (i.e., angular velocity) and (b) yarn diameter.

The lappet holder 7 (as partly illustrated in FIGS. 2 to 4) comprises a body 10 in which is located an annular yarn guide or eyelet 11 which is normally of a hard ceramic material. The body 10 is of a plastics material which can either be moulded or machined to have two holes. The two holes are opposed and in line on an axis which forms a chord of the hole 12 and provide housings in which the light source 9 and detector 8 are respectively mounted (see FIG. 3).

The light from source 9 is directed onto the detector 8 and is arranged to provide a substantially parallel and narrow beam. The light source is conveniently a tungsten filament type lamp or an infrared emittor. The light beam impinges on the light-sensitive device 8 through an aperture 13. The aperture 13 (illustrated in FIG. 4) is preferably a slit which extends substantially parallel to the direction of the longitudinal movement of the yam 2. The yarn is fed through the guide 11 and exhibits ballooning 2a, thereby intersecting the light beam from source 9. During ballooning, the momentum of yarn as a result of its angular movement causes it to be offset from the longitudinal direction and, if necessary, the slit aperture 13 can be similarly offset from the longitudinal direction (as shown at 13a in FIG. 4) to approximately the same amount to ensure that the yarn passes laterally across the slit and substantially parallel thereto.

As the yarn 2 is being wound onto the spindle 5 it balloons at 2a and as a result, on every cycle the yarn passes sequentially very close both to the aperture 13 and to the light source 9 and in so doing reduces the light intensity on the detector 8 for a given period. This period depends on the angular velocity and also on yarn diameter.

The signals produced by the variation in light intensity on the light-sensitive device can then be processed and passed to an output stage in several ways, all of which will generally have a similar result, i.e., to open or close an electronic or electromechanical gate, typical examples of these are the switching of a transistor (or other semiconductor devices) or the operating of a relay. The function of the output stage can be employed to operate other devices such as a warning light or bell or to trigger a yam-cutting device.

The form of detecting system illustrated in FIG. 5 is respon sive to variations in light intensity on the light-sensitive device 8 and the signals from detector 8 are passed to an amplifier 14 and then to a monostable multivibrator 15 the output from which is passed to an output stage 16. The waveforms as a result of the variations in light intensity to the detector 8 are shown respectively at 8a and 14a to 16a. The pulses 8a produced by the interruption on the light beam by the ballooning yarn are amplified at 14a, the effect of this train of amplified pulses on the multivibrator 15 is to produce a waveform as shown at 15a. Normally the output stage 16 for from the monostable circuit combined with the capacitor across the coil ensure that the relay is held in the ON" condition while the yarn is running. When as, for example, a break in the yarn occurs, the pulses 8a cease and the monostable multivibrator 15 switches to the OFF condition thus allowing the output state 16 to be deenergized and therefore switching the contacts into the OFF position.

By using contacts of the relay for the output stage 16, action can be taken on the information supplied by the detector 8.

Because the detecting system above described with reference to FIG. 5 is actuated by laterally moving the yarn,

the output changes condition only when the yarn movement either starts or stops, i.e., it is in a stable condition while the yarn is moving and in a contrary condition while the yarn is stopped. It will be apparent from this that the actual time of running yarn through the lappet 10 can be recorded simply and accurately. The method of recording can be as illustrated in FIG. 6, where a clock pulse 17 derived from a suitable generator 17a (which clock pulse could be at intervals of one second, or any other suitable period) is fed into the output stage 16 of the system, e.g., through the contacts of the output relay) depending as to whether the output is open or closed the pulses 17 are passed onto a standard recording device 19. The timing device 19 could be, for example, a counter which would record, in seconds, the period of time for the run of the yarn from which the length of run can be calculated.

This system of recording the length of time of a run of yarn is very important in certain sections of the textile trade, especially when it is highly desirable to have final packages 6 of constant length. If necessary an automatic cutoff can be provided on the recorder so that the winding machine is stopped when a required run has been wound.

Should one winding part of a machine (i.e., one spindle) not be operating as efficiently as other spindles on the frame, that is to say it suffers more down time; the resulting smaller package 6 can be identified readily from its counter. The fact that this identification is possible enables final packages to be graded in length from the time factor and therefore when this package is mounted, for example, on a creel with many other packages, it does not hinder production or waste material if its is used with other packages of a similar time record.

For convenience, description of the complete electrical circuitry of the yarn detection systems above described has been omitted, it being realized that the construction and operation of such circuits is completely within the everyday working knowledge of a person skilled in the relevant art and having an understanding of the present invention.

What I claim is: I. In a method of yarn-handling in which the yarn is laterally displaced as it moves longitudinally between a laterally fixed position and a laterally moving position which moving position is longitudinally spaced from said fixed position; an improved method of detecting said yarn which comprises intermittently and repeatedly passing the yarn, during its lateral displacement between said positions, through a light beam which is rectilinearly directed on to a lightsensitive device responsive to the beam so that the intensity of light from the beam on said device is repeatedly and intermittently decreased and increased; detecting the period for which the beam is interrupted during each lateral movement of the yarn therethrough and emitting signals in response to said detected periods to means adapted to be actuated in response to the discontinuance of said emitted signals.

2. A method as claimed in claim 8 in which the laterally moving position describes a substantially laterally disposed circle so that the longitudinally moving yarn between the fixed position and laterally moving positions exhibits ballooning," and wherein the ballooning yarn repeatedly interrupts the beam of light twice during each revolution of the yarn which describes the balloon.

3. In yarn-handling apparatus which includes means longitudinally moving the yarn relative to a laterally fixed position and displacement means imparting lateral movement to the yarn to provide a laterally moving position of the yarn which moving position is longitudinally spaced from said laterally fixed position; an improved means for detecting said yarn, which comprises a light source and a light-sensitive device, said light source providing a light beam which is rectilinearly directed on to said light-sensitive device which light-sensitive device is responsive to the intensity of said beam;

said light source and light-sensitive device being located so that the beam is repeatedly and intermittently interrupted by the yarn at a position between said laterally fixed position and said laterally moving position whereby the intensity of light from the beam on said device is repeatedly and intermittently decreased and increased;

means for detecting the period for which the beam is interrupted during each lateral movement of the yarn thercthrough and for emitting signals in response to said detected periods; and

means receiving said emitted signals which means is adapted to be actuated in response to the discontinuance of said emitted signals.

4. Yarn-handling apparatus as claimed in claim 3, wherein said displacement means imparts a centrifugal force to the longitudinally moving yarn so that said laterally moving position describes a substantially laterally disposed circle and the longitudinally moving yarn between the laterally fixed position and laterally moving position exhibits ballooning;" and wherein said light source and light-sensitive device are located so that the beam is interrupted twice during each revolution of the yarn which describes the balloon.

5. Yarn-handling apparatus as claimed in claim 3, which includes a lappet holder having an eyelet through which said longitudinally moving yarn is fed and wherein said light source and light-sensitive device are carried by said lappet holder. 

1. In a method of yarn-handling in which the yarn is laterally displaced as it moves longitudinally between a laterally fixed position and a laterally moving position which moving position is longitudinally spaced from said fixed position; an improved method of detecting said yarn which comprises intermittently and repeatedly passing the yarn, during its lateral displacement between said positions, through a light beam which is rectilinearly directed on to a light-sensitive device responsive to the beam so that the intensity of light from the beam on said device is repeatedly and intermittently decreased and increased; detecting the period for which the beam is interrupted during each lateral movement of the yarn therethrough and emitting signals in response to said detected periods to means adapted to be actuated in response to the discontinuance of said emitted signals.
 2. A method as claimed in claim 8 in which the laterally moving position describes a substantially laterally disposed circle so that the longitudinally moving yarn between the fixed position and laterally moving positions exhibits ''''ballooning,'''' and wherein the ballooning yarn repeatedly interrupts the beam of light twice during each revolution of the yarn which describes the balloon.
 3. In yarn-handling apparatus which includes means longitudinally moving the yarn relative to a laterally fixed position and displacement means imparting lateral movement to the yarn to provide a laterally moving position of the yarn which moving position is longitudinally spaced from said laterally fixed position; an improved means for detecting said yarn, which comprises a light source and a light-sensitive device, said light source providing a light beam which is rectilinearly directed on to said light-sensitive device which light-sensitive device is responsive to the intensity of said beam; said light source and light-sensitive device being located so that the beam is repeatedly and intermittently interrupted by the yarn at a position between said laterally fixed position and said laterally moving position whereby the intensity of light from the beam on said device is repeatedly and intermittently decreased and increased; means for detecting the period for which the beam is interrupted during each lateral movement of the yarn therethrough and for emitting signals in response to said detected periods; and means receiving said emitted signals which means is adapted to be actuated in response to the discontinuance of said emitted signals.
 4. Yarn-handling apparatus as claimed in claim 3, wherein said displacement means imparts a centrifugal force to the longitudinally moving yarn so that said laterally moving position describes a substantially laterally disposed circle and the longitudinally moving yarn between the laterally fixed position and laterally moving position exhibits ''''ballooning; '''' and wherein said light source and light-sensitive device are located so that the beam is interrupted twice during each revolution of the yarn which describes the balloon.
 5. Yarn-handling apparatus as claimed in claim 3, which includes a lappet holder having an eyelet through which said longitudinally moving yarn is fed and wherein said light source and light-sensitive device are carried by said lappet holder. 